Vibrating diaphragm for sound production device, sound production device and electronic equipment

Abstract

The invention discloses a vibrating diaphragm for a sound production device, the sound production device and electronic equipment. The vibrating diaphragm comprises at least one thermoplastic polyester elastomer layer; the thermoplastic polyester elastomer layer is prepared from a blending material, and the blending material comprises a first thermoplastic polyester elastomer and a second thermoplastic polyester elastomer; the glass transition temperature of the first thermoplastic polyester elastomer is-65 DEG C to-30 DEG C, the glass transition temperature of the second thermoplastic polyester elastomer is-25 DEG C to 0 DEG C, and the creep recovery rate of the thermoplastic polyester elastomer layer in 5 minutes is 70%-99%. The vibrating diaphragm comprises at least one thermoplastic polyester elastomer layer; the thermoplastic polyester elastomer layer is prepared from a blended material. The thermoplastic polyester elastomer film layer comprises thermoplastic polyester elastomers with different glass transition temperatures, so that the low-temperature performance is ensured, good damping can be provided, and the sound production effect of the vibrating diaphragm can be further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroacoustic conversion, and more particularly to a diaphragm for a sound-generating device, a sound-generating device, and an electronic device. Background Art

[0002] In related technologies, the diaphragms of speakers, especially micro speakers, are typically made of engineering plastics (such as polyetheretherketone (PEEK), elastomers (such as thermoplastic polyester elastomer (TPEE), and rubbers (such as ethylene-acrylate rubber (AEM)). TPEE is a popular diaphragm material due to its advantages such as simple design, easy processing, and low cost.

[0003] However, the damping performance of TPEE materials is poor. In the process of pursuing the improvement of the damping performance of TPEE materials, other properties, such as the creep recovery rate of the diaphragm, are significantly reduced, thereby reducing the overall performance of the TPEE diaphragm. Summary of the Invention

[0004] An object of the present invention is to provide a new technical solution for a diaphragm of a sound-generating device.

[0005] According to a first aspect of the present invention, a diaphragm for a sound-generating device is provided. The diaphragm comprises at least one thermoplastic polyester elastomer layer; the thermoplastic polyester elastomer layer is made of a blended material comprising a first thermoplastic polyester elastomer and a second thermoplastic polyester elastomer; the first thermoplastic polyester elastomer has a glass transition temperature of -65°C to -30°C, and the ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first and second thermoplastic polyester elastomers is 30%-95%; the second thermoplastic polyester elastomer has a glass transition temperature of -25°C to 0°C, and the ratio of the mass of the second thermoplastic polyester elastomer to the total mass of the first and second thermoplastic polyester elastomers is 5%-70%; and the thermoplastic polyester elastomer layer has a 5-minute creep recovery rate of 70%-99%.

[0006] Optionally, the ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 70%-90%, and the ratio of the mass of the second thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 10%-30%.

[0007] Optionally, the soft segment of the first thermoplastic polyester elastomer includes at least one of polytetrahydrofuran, polypropylene oxide, and polyethylene oxide, the mass percentage of the soft segment of the first thermoplastic polyester elastomer is 40%-80%, and the relative molecular weight of the soft segment of the first thermoplastic polyester elastomer is 1000-5000.

[0008] Optionally, the soft segment of the second thermoplastic polyester elastomer includes at least one of aliphatic polyester, aromatic-aliphatic copolyester, aliphatic polycarbonate, aromatic polyether, and copolyether, the mass percentage of the soft segment of the second thermoplastic polyester elastomer is 30%-60%, and the relative molecular weight of the soft segment of the second thermoplastic polyester elastomer is 800-3000.

[0009] Optionally, the blended material further comprises an antioxidant, wherein the antioxidant comprises at least one of a hindered phenol antioxidant, a phosphite antioxidant, and a thioether antioxidant, and the amount of the antioxidant added to the blended material is 0.1 phr-7 phr; And / or, the blended material further comprises an anti-hydrolysis agent, the anti-hydrolysis agent comprises at least one of monomeric carbodiimide, polycarbodiimide, and polycarbodiimide, and the amount of the anti-hydrolysis agent added to the blended material is 0.5 phr-5 phr; And / or, the blended material further comprises a light stabilizer, the light stabilizer comprising at least one of a benzotriazole light stabilizer, a triazine light stabilizer, a hindered amine light stabilizer, and a nickel quencher, and the light stabilizer is added to the blended material in an amount of 0.1 phr to 2 phr; And / or, the blended material further comprises a colorant, the colorant comprising at least one of phthalocyanine blue, phthalocyanine green, azo red, titanium dioxide, red iron oxide, carbon black, anthraquinones, and aluminum powder, and the amount of the colorant added to the blended material is 0.1 phr-5 phr; And / or, the blended material further includes a processing aid, which includes at least one of erucamide, oleamide, silica, diatomaceous earth, polydimethylsiloxane, ethylene wax, talc, and stearic acid additives, and the amount of the processing aid added to the blended material is 0.1phr-10phr.

[0010] Optionally, the thickness of the thermoplastic polyester elastomer layer is 5 μm-100 μm; and / or, the Young's modulus of the thermoplastic polyester elastomer layer at room temperature is 20 MPa-600 MPa; And / or, the density of the thermoplastic polyester elastomer layer is 1.10 g / cm 3 -1.30g / cm 3 .

[0011] Optionally, the melting temperature of the thermoplastic polyester elastomer layer is ≥185°C.

[0012] Optionally, the ratio of the melt index of the first thermoplastic polyester elastomer to the melt index of the second thermoplastic polyester elastomer is 0.5-2.

[0013] Optionally, after heat treatment at 160° C. for 96 hours, the thermoplastic polyester elastomer layer has a tensile strength decrease rate of ≤50%, and a Young's modulus decrease rate of ≤20%.

[0014] Optionally, the diaphragm is formed into a single-layer structure, and the diaphragm is composed of a layer of the thermoplastic polyester elastic layer; Alternatively, the diaphragm is formed into a multi-layer structure, the diaphragm includes at least one layer of the thermoplastic polyester elastomer layer and a composite layer, the composite layer and the thermoplastic polyester elastomer layer are stacked, and the composite layer is at least one of rubber, silicone, and engineering plastic.

[0015] According to a second aspect of the present invention, a sound-generating device is provided, which includes the diaphragm of the present invention.

[0016] According to a third aspect of the present invention, an electronic device is provided, which includes the sound-generating device of the present invention.

[0017] In an embodiment of the present invention, the diaphragm includes at least one thermoplastic polyester elastomer layer; the thermoplastic polyester elastomer layer is made from a blended material. Because the thermoplastic polyester elastomer film layer comprises thermoplastic polyester elastomers with different glass transition temperatures, it ensures both low-temperature performance and excellent damping, thereby enhancing the diaphragm's acoustic performance. Furthermore, the thermoplastic polyester elastomer layer in this embodiment of the present invention exhibits a 5-minute creep recovery rate of 70%-99%, maintaining the diaphragm's creep and damping within a reasonable range and demonstrating strong deformation recovery after creep.

[0018] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0020] Figure 1 is a cross-sectional view of a diaphragm according to an embodiment of the present invention.

[0021] Figure 2 is a perspective view of a sound-generating device according to an embodiment of the present invention.

[0022] Figure 3is a cross-sectional view of a sound generating device according to an embodiment of the present invention.

[0023] Figure 4 1 is a total harmonic distortion (THD) curve of the sound-generating device of the embodiment of the present invention and the comparative example.

[0024] Reference numerals: 100. Sound-generating device; 10. Housing; 20. Diaphragm; 30. Voice coil; 40. Permanent magnet. DETAILED DESCRIPTION

[0025] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0026] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0027] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0028] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0029] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0030] The following describes in detail the diaphragm 20 for a sound-generating device according to an embodiment of the present invention with reference to the accompanying drawings.

[0031] According to one embodiment of the present invention, a diaphragm 20 for a sound-generating device is provided. The diaphragm 20 includes at least one thermoplastic polyester elastomer layer; the thermoplastic polyester elastomer layer is made of a blended material comprising a first thermoplastic polyester elastomer and a second thermoplastic polyester elastomer; the first thermoplastic polyester elastomer has a glass transition temperature of -65°C to -30°C, and the ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first and second thermoplastic polyester elastomers is 30%-95%; the second thermoplastic polyester elastomer has a glass transition temperature of -25°C to 0°C, and the ratio of the mass of the second thermoplastic polyester elastomer to the total mass of the first and second thermoplastic polyester elastomers is 5%-70%; and the thermoplastic polyester elastomer layer has a 5-minute creep recovery rate of 70%-99%.

[0032] Specifically, the diaphragm 20 is applied to a sound-generating device, such as a miniature sound-generating device. The diaphragm 20 serves as a part of a vibration system. The diaphragm 20 is a ring-shaped diaphragm or a flat diaphragm. Optionally, the diaphragm 20 includes a thermoplastic polyester elastomer layer. The thermoplastic polyester elastomer layer may be one layer or multiple layers. The thermoplastic polyester elastomer layer is prepared using a blended material. The preparation method is, for example, air pressure molding. The blended material is mixed by a plurality of materials, for example, a plurality of materials are added to an extruder. Blending is performed in the extruder and the mixture is evenly mixed to form a blended material.

[0033] Thermoplastic polyester elastomer (TPEE) is formed by block copolymerization of polyester hard segments and polyester or polyether soft segments. The blended material includes two thermoplastic polyester elastomers with different glass transition temperatures, namely a first thermoplastic polyester elastomer with a low glass transition temperature and a second thermoplastic polyester elastomer with a high glass transition temperature. The glass transition temperature of the first thermoplastic polyester elastomer is -65°C to -30°C, and the glass transition temperature of the second thermoplastic polyester elastomer is -25 to 0°C. During preparation, the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer are added to an extruder. Blending is carried out in the extruder to finally form a blended material. The blended material can be used to prepare a thermoplastic polyester elastomer layer by casting or coating, and the thermoplastic polyester elastomer layer is formed by air pressure to obtain a diaphragm 20.

[0034] The ratio of the mass of the first thermoplastic polyester elastomer to the sum of the mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 30%-95%. Correspondingly, the ratio of the mass of the second thermoplastic polyester elastomer to the sum of the mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 5%-70%.

[0035] In this embodiment, the damping of the diaphragm 20 is related to the ratio of the high glass transition temperature component to the low glass transition temperature component. By limiting the ratio of the first thermoplastic polyester elastomer to the second thermoplastic polyester elastomer in the blended material, the diaphragm 20 can have higher damping.

[0036] When the ratio of the mass of the first thermoplastic polyester elastomer to the sum of the masses of the first and second thermoplastic polyester elastomers is less than 30%, and accordingly, the ratio of the mass of the second thermoplastic polyester elastomer to the sum of the masses of the first and second thermoplastic polyester elastomers is greater than 70%, in this case, the content of the first thermoplastic polyester elastomer is too low, and the acoustic performance of the diaphragm 20 at low temperature (-20°C) differs significantly from that at room temperature (23°C). When the ratio of the mass of the first thermoplastic polyester elastomer to the sum of the masses of the first and second thermoplastic polyester elastomers is greater than 95%, and accordingly, the ratio of the mass of the second thermoplastic polyester elastomer to the sum of the masses of the first and second thermoplastic polyester elastomers is less than 5%, in this case, the content of the second thermoplastic polyester elastomer is too low, and the dissipation factor of the diaphragm 20 is small, resulting in large distortion. When the ratio of the mass of the first thermoplastic polyester elastomer to the sum of the masses of the first and second thermoplastic polyester elastomers is 30%-95%; correspondingly, the ratio of the mass of the second thermoplastic polyester elastomer to the sum of the masses of the first and second thermoplastic polyester elastomers is 5%-70%. Within this range, the diaphragm 20 has good damping performance and excellent low-temperature performance.

[0037] In this embodiment of the present invention, the diaphragm 20 includes at least one thermoplastic polyester elastomer layer; this thermoplastic polyester elastomer layer is made from a blended material. Because the thermoplastic polyester elastomer film layer includes a second thermoplastic polyester elastomer, it effectively improves the damping of the diaphragm 20, maintaining good damping stability over a wide operating temperature range and amplitude range. Furthermore, the thermoplastic polyester elastomer layer of this embodiment of the present invention has a 5-minute creep recovery rate of 70%-99%, maintaining the creep recovery rate and damping of the diaphragm 20 within a reasonable range.

[0038] The creep recovery rate is the percentage of the reduction in strain of the material within a set time after the tensile load is unloaded to the strain at the time of unloading. The creep recovery rate characterizes the ability of the material to recover from deformation after creep. If the creep recovery rate is too small, the thermoplastic polyurethane elastomer layer will have poor ability to recover from deformation after creep; if the creep recovery rate is too large, the damping performance of the thermoplastic polyurethane elastomer layer will decrease. The 5-minute creep recovery rate of the thermoplastic polyurethane elastomer layer of the embodiment of the present invention is 70%-99%, so that the diaphragm 20 has both good damping performance and strong ability to recover from deformation after creep.

[0039] Among them, the creep recovery rate test method can be based on GB / T 11546.1-2008 standard, with a stress of 0.1 MPa, a holding time of 5 minutes, a creep time of 10 minutes, and a recovery time of 5 minutes.

[0040] Optionally, the ratio of the mass of the first thermoplastic polyester elastomer to the sum of the masses of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 30%, 40%, 50%, 60%, 70%, 80%, 95%, etc. The ratio of the mass of the second thermoplastic polyester elastomer to the sum of the masses of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, etc. The 5-minute creep recovery rate of the thermoplastic polyester elastomer layer is 70%, 75%, 80%, 85%, 90%, 99%, etc. Those skilled in the art can adjust the creep recovery rate according to actual needs.

[0041] In some specific embodiments of the present invention, the ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 70%-90%, and the ratio of the mass of the second thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 10%-30%.

[0042] In this embodiment, by further optimizing the ratio of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer, that is, the ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 70%-90%, and the ratio of the mass of the second thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 10%-30%, the damping of the diaphragm 20 can be more effectively improved, the damping effect is better, and the low-temperature performance is excellent.

[0043] In some specific embodiments of the present invention, the soft segment of the first thermoplastic polyester elastomer includes at least one of polytetrahydrofuran, polypropylene oxide, and polyethylene oxide, the mass percentage of the soft segment of the first thermoplastic polyester elastomer is 40%-80%, and the relative molecular weight of the soft segment of the first thermoplastic polyester elastomer is 1000-5000.

[0044] In this embodiment, the soft segment of the first thermoplastic polyester elastomer includes one or more thermoplastic polyester elastomers selected from polytetramethylene oxide, polypropylene oxide, and polyethylene oxide, all of which meet the glass transition temperature requirements of the first thermoplastic polyester elastomer.

[0045] Furthermore, by adjusting the ratio of the soft segment to the hard segment and the relative molecular weight of the soft segment in the first thermoplastic polyester elastomer, the performance of the first thermoplastic polyester elastomer can be further optimized. When the soft segment content of the first thermoplastic polyester elastomer is less than 40% by weight, the hard segment content is correspondingly too high, resulting in excessive hardness, poor elasticity, a high glass transition temperature, and insufficient low-temperature performance of the diaphragm 20. When the soft segment content of the first thermoplastic polyester elastomer is greater than 80% by weight, the soft segment transitions from a dispersed phase to a continuous phase, resulting in poor dimensional stability, significant permanent deformation, poor heat resistance, insufficient hardness, poor mechanical properties, and a low glass transition temperature. When the soft segment content of the first thermoplastic polyester elastomer is between 40% and 80% by weight, the diaphragm 20 has a moderate glass transition temperature and hardness, while also maintaining moderate low-temperature and heat resistance.

[0046] When the relative molecular weight of the soft segment of the first thermoplastic polyester elastomer is less than 1000, the hardness of the diaphragm 20 is too high; when the relative molecular weight of the soft segment of the first thermoplastic polyester elastomer is greater than 5000, the hardness of the diaphragm 20 is too low; when the relative molecular weight of the soft segment of the first thermoplastic polyester elastomer is 1000-5000, the hardness of the diaphragm 20 is moderate.

[0047] Optionally, the mass content of the soft segment of the first thermoplastic polyester elastomer is 40%, 50%, 60%, 70%, 80%, etc.; the relative molecular weight of the soft segment of the first thermoplastic polyester elastomer is 1000, 2000, 3000, 4000, 5000, etc., and those skilled in the art can make a selection according to actual needs.

[0048] In some specific embodiments of the present invention, the soft segment of the second thermoplastic polyester elastomer includes at least one of an aliphatic polyester, an aromatic-aliphatic copolyester, an aliphatic polycarbonate, an aromatic polyether, and a copolyether, the mass percentage of the soft segment of the second thermoplastic polyester elastomer is 30%-60%, and the relative molecular weight of the soft segment of the second thermoplastic polyester elastomer is 800-3000.

[0049] In this embodiment, the second thermoplastic polyester elastomer is selected from a thermoplastic polyester elastomer having a soft segment comprising one or more of aliphatic polyesters, aromatic-aliphatic copolyesters, aliphatic polycarbonates, aromatic polyethers, and copolyethers. All of these materials meet the glass transition temperature requirements of the second thermoplastic polyester elastomer.

[0050] Furthermore, by adjusting the ratio of the soft segment to the hard segment in the second thermoplastic polyester elastomer, and adjusting the soft segment relative to the molecular chain, the performance of the second thermoplastic polyester elastomer can be further optimized. When the soft segment content of the second thermoplastic polyester elastomer is less than 30% by weight, the hard segment content is correspondingly too high, resulting in excessive hardness, poor elasticity, a high glass transition temperature, and insufficient low-temperature performance of the diaphragm 20. When the soft segment content of the second thermoplastic polyester elastomer is greater than 60% by weight, the soft segment transitions from a dispersed phase to a continuous phase, resulting in poor dimensional stability, large permanent deformation, poor heat resistance, insufficient hardness, poor mechanical properties, and a low glass transition temperature. When the soft segment content of the second thermoplastic polyester elastomer is between 30% and 60% by weight, the diaphragm 20 has a moderate glass transition temperature and hardness, while also maintaining moderate low-temperature and heat resistance.

[0051] When the relative molecular weight of the soft segment of the second thermoplastic polyester elastomer is less than 800, the hardness of the diaphragm 20 is too high; when the relative molecular weight of the soft segment of the second thermoplastic polyester elastomer is greater than 3000, the hardness of the diaphragm 20 is too low; when the relative molecular weight of the soft segment of the second thermoplastic polyester elastomer is 800-3000, the hardness of the diaphragm 20 is moderate.

[0052] Optionally, the mass content of the soft segment of the second thermoplastic polyester elastomer is 30%, 40%, 50%, 60%, etc.; the relative molecular weight of the soft segment of the second thermoplastic polyester elastomer is 800, 1000, 2000, 3000, etc., and those skilled in the art can make a selection according to actual needs.

[0053] In some specific embodiments of the present invention, the blended material further comprises an antioxidant, wherein the antioxidant comprises at least one of a hindered phenol antioxidant, a phosphite antioxidant, and a thioether antioxidant, and the amount of the antioxidant added to the blended material is 0.1 phr-7 phr; And / or, the blended material further comprises an anti-hydrolysis agent, the anti-hydrolysis agent comprises at least one of monomeric carbodiimide, polycarbodiimide, and polycarbodiimide, and the amount of the anti-hydrolysis agent added to the blended material is 0.5 phr-5 phr; And / or, the blended material further comprises a light stabilizer, the light stabilizer comprising at least one of a benzotriazole light stabilizer, a triazine light stabilizer, a hindered amine light stabilizer, and a nickel quencher, and the light stabilizer is added to the blended material in an amount of 0.1 phr to 2 phr; And / or, the blended material further comprises a colorant, the colorant comprising at least one of phthalocyanine blue, phthalocyanine green, azo red, titanium dioxide, red iron oxide, carbon black, anthraquinones, and aluminum powder, and the amount of the colorant added to the blended material is 0.1 phr-5 phr; And / or, the blended material further includes a processing aid, which includes at least one of erucamide, oleamide, silica, diatomaceous earth, polydimethylsiloxane, ethylene wax, talc, and stearic acid additives, and the amount of the processing aid added to the blended material is 0.1phr-10phr.

[0054] In an embodiment of the present invention, the antioxidant can inhibit the oxidative degradation of TPEE during processing or long-term use, thereby improving the reliability of the diaphragm 20. Any one or a mixture of hindered phenol antioxidants, phosphite antioxidants, and thioether antioxidants can be selected from the blending material. The amount of antioxidant added to the blending material is 0.1phr-7phr, which means that 0.1 parts by mass to 7 parts by mass are added to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 100 parts by mass. When the amount of the antioxidant added to the blending material is less than 0.1phr, the effect of the antioxidant in inhibiting the oxidative degradation of TPU is not obvious. When the amount of the antioxidant added to the blending material is greater than 7phr, the antioxidant is easily precipitated. When the amount of the antioxidant added to the blending material is 0.1phr-7phr, the effect of the antioxidant in inhibiting the oxidative degradation of TPEE is significant and is not easy to precipitate.

[0055] The anti-hydrolysis agent can improve the water resistance of TPEE, prevent TPEE from hydrolyzing in a humid environment, and improve the reliability of the diaphragm 20. Any one or a mixture of monomeric carbodiimide, polycarbodiimide, and polycarbodiimide can be selected in the blending material. The amount of the anti-hydrolysis agent added to the blending material is 0.5phr-5phr, which means that 0.5-5 parts by mass are added to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 100 parts by mass. When the amount of the anti-hydrolysis agent added to the blending material is less than 0.5phr, the effect of the anti-hydrolysis agent on improving the water resistance of TPEE is not obvious. When the amount of the anti-hydrolysis agent added to the blending material is greater than 5phr, the anti-hydrolysis agent is easy to precipitate. When the amount of the anti-hydrolysis agent added to the blending material is 0.5phr-5phr, the effect of the anti-hydrolysis agent on improving the water resistance of TPEE is significant and not easy to precipitate.

[0056] Light stabilizers can inhibit the photooxidative degradation of TPEE during processing, manufacturing and use, and improve the reliability of the diaphragm 20. The blended material can contain any one or a mixture of benzotriazole light stabilizers, triazine light stabilizers, hindered amine light stabilizers, and nickel quenchers. The amount of light stabilizer added to the blended material is 0.1phr-2phr, which means that 0.1-2 parts by mass are added to 100 parts by mass of the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer. When the amount of light stabilizer added to the blended material is less than 0.1phr, the effect of the light stabilizer in inhibiting the photooxidative degradation of TPEE during processing, manufacturing and use is not obvious. When the amount of light stabilizer added to the blended material is greater than 2phr, the light stabilizer is easy to precipitate. When the amount of light stabilizer added to the blended material is 0.1phr-2phr, the light stabilizer significantly slows down the photooxidative degradation of TPEE and inhibits the photooxidative degradation of TPEE during processing, manufacturing and use, and is not easy to precipitate.

[0057] The colorant can absorb visible light of a set wavelength, giving the TPEE a set color. The blend material can be selected from a mixture of one or more of phthalocyanine blue, phthalocyanine green, azo red, titanium dioxide, red iron oxide, carbon black, anthraquinones, and aluminum powder. The amount of the colorant added to the blend material is 0.1 phr to 5 phr, which means that 0.1 to 5 parts by mass are added to 100 parts by mass of the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer. The amount of the colorant added to the blend material is 0.1 to 5 phr, which makes the TPEE coloring obvious and prevents the colorant from precipitating.

[0058] Processing aids can improve the fluidity of TPEE, reduce the melt viscosity of TPEE, and prevent TPEE from melting and fracturing, thereby optimizing the processing performance of TPEE. The blending material can be selected from any one of erucamide, oleamide, silica, diatomaceous earth, polydimethylsiloxane, ethylene wax, talc, and stearic acid, or a mixture of multiple types. The amount of processing aid added to the blending material is 0.1 phr-10 phr, which means that 0.1 to 10 parts by mass are added to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 100 parts by mass. When the amount of processing aid added to the blending material is less than 0.1 phr, the effect of the processing aid on optimizing the processing performance of TPEE is not obvious. When the amount of processing aid added to the blending material is greater than 10 phr, the processing aid is easy to precipitate. When the amount of processing aid added to the blending material is 0.1 phr-10 phr, the effect of processing aid on optimizing the processing performance of TPEE is significant and is not easy to precipitate.

[0059] In some specific embodiments of the present invention, the thickness of the thermoplastic polyester elastomer layer is 5 μm-100 μm; and / or, the Young's modulus of the thermoplastic polyester elastomer layer at room temperature is 20 MPa-600 MPa; And / or, the density of the thermoplastic polyester elastomer layer is 1.10 g / cm 3 -1.30g / cm 3 .

[0060] In this embodiment, the thermoplastic polyester elastomer layer can be used to prepare the diaphragm 20 by an extrusion casting process. The thickness of the diaphragm 20 has an important influence on the performance of the diaphragm 20. When the thickness of the diaphragm 20 is too low, for example, less than 5μm, the diaphragm 20 is easily deformed during processing, which is not conducive to the processing and molding of the diaphragm 20. When the thickness of the diaphragm 20 is too high, for example, greater than 100μm, the vibration space of the diaphragm 20 is affected, and the diaphragm 20 is easily rubbed against the shell. When the thickness of the diaphragm 20 is 5μm-100μm, it can not only ensure the convenience of processing of the diaphragm 20, but also save the vibration space of the diaphragm 20.

[0061] Optionally, the thickness of the diaphragm 20 is 5 μm, 40 μm, 50 μm, 80 μm, 100 μm, etc., and those skilled in the art can set it according to actual needs.

[0062] The Young's modulus of the thermoplastic polyester elastomer layer has an important influence on the thickness of the diaphragm 20. When the Young's modulus of the thermoplastic polyester elastomer layer is less than 20 MPa, the thickness of the thermoplastic polyester elastomer layer needs to be increased to meet the set frequency response curve requirements; otherwise, the thickness of the thermoplastic polyester elastomer layer needs to be reduced. If the Young's modulus of the thermoplastic polyester elastomer layer is too low, the thickness of the diaphragm 20 will be too large and the mass will be too large, which will ultimately lead to poor mid-frequency performance of the diaphragm 20, limited vibration space, large signal distortion, etc. When the Young's modulus of the thermoplastic polyester elastomer layer is greater than 600 MPa, the thickness of the thermoplastic polyester elastomer is too small, the processing accuracy of the equipment cannot meet the production requirements of the diaphragm 20, and the vibration consistency of the diaphragm 20 is poor. When the room temperature Young's modulus of the thermoplastic polyester elastomer layer is 20 MPa-600 MPa, the thickness of the diaphragm 20 is moderate, the mid-frequency performance is excellent, the distortion is small, the processing is easy, and the vibration consistency is good.

[0063] Optionally, the Young's modulus of the thermoplastic polyester elastomer layer is 20 MPa, 50 MPa, 100 MPa, 150 MPa, 200 MPa, 300 MPa, 400 MPa, 500 MPa, 600 MPa, etc., and those skilled in the art can set it according to actual needs.

[0064] In some specific embodiments of the present invention, the melting temperature of the thermoplastic polyester elastomer layer is ≥185°C.

[0065] In this embodiment, the melting temperature of the thermoplastic polyester elastomer layer is ≥185° C., so that the diaphragm 20 has good temperature resistance during long-term use.

[0066] Optionally, the melting temperature of the thermoplastic polyester elastomer layer is ≥195° C. Within this range, the diaphragm 20 has better temperature resistance during long-term use.

[0067] In some specific embodiments of the present invention, the ratio of the melt index of the first thermoplastic polyester elastomer to the melt index of the second thermoplastic polyester elastomer is 0.5-2.

[0068] Specifically, thermoplastic polyester elastomers are typically blended using an extruder. Extruders require the melt indexes of the blended components to be similar to ensure similar melt viscosities during the extrusion casting process. In the embodiments of the present invention, the ratio of the melt index of the first thermoplastic polyester elastomer to the melt index of the second thermoplastic polyester elastomer is 0.5-2. This similar melt index of the first and second thermoplastic polyester elastomers effectively avoids poor material plasticization and uneven dispersion caused by differences in melt viscosity, ensuring consistent cast film thickness.

[0069] Optionally, the ratio of the melt index of the first thermoplastic polyester elastomer to the melt index of the second thermoplastic polyester elastomer is 0.7-1.3, which makes it easy to mix the thermoplastic polyester elastomers evenly.

[0070] In some specific embodiments of the present invention, the thermoplastic polyester elastomer layer has a tensile strength change rate of ≤50% and a Young's modulus change rate of ≤20% after heat treatment at 160° C. for 96 hours.

[0071] In this embodiment, the thermoplastic polyester elastomer layer was heat-treated at 160°C for 96 hours. The change in tensile strength and Young's modulus before and after the treatment were used to calculate the rate of change in tensile strength and Young's modulus relative to the thermoplastic polyester elastomer layer before and after treatment. Higher rates of change in tensile strength and Young's modulus indicate poor heat resistance and reliability of the thermoplastic polyester elastomer layer, as well as the presence of membrane breakage. The thermoplastic polyester elastomer layer of the embodiment of the present invention had a tensile strength change of ≤50% and a Young's modulus change of ≤20% after heat treatment, resulting in excellent heat resistance and reliability of the diaphragm 20.

[0072] Optionally, the tensile strength change rate of the thermoplastic polyester elastomer layer after heat treatment at 160°C for 96 hours is ≤30%, and the Young's modulus change rate is ≤10%, which makes the heat resistance of the diaphragm 20 better and the reliability of the diaphragm 20 better.

[0073] It should be noted that after the high temperature treatment and / or high temperature and high humidity treatment, the Young's modulus of the diaphragm 20 may decrease or increase.

[0074] In some specific embodiments of the present invention, the diaphragm is formed into a single-layer structure, and the diaphragm is composed of a layer of the thermoplastic polyester elastomer; Alternatively, the diaphragm is formed into a multi-layer structure, the diaphragm includes at least one layer of the thermoplastic polyester elastomer layer and a composite layer, the composite layer is stacked with the thermoplastic polyester elastomer layer, and the composite layer is at least one of an elastomer layer, an engineering plastic layer and a film layer.

[0075] That is to say, the diaphragm of the embodiment of the present invention can be a single-layer thermoplastic polyester elastomer layer. The diaphragm has a simple structure and a simple preparation process.

[0076] Alternatively, the diaphragm may have a multi-layer structure. Specifically, at least one thermoplastic polyester elastomer layer and a composite layer are laminated together to form a multi-layer diaphragm. The composite layer is at least one of an elastomer layer, an engineering plastic layer, and a film layer. The multi-layer structure may have 2, 3, 4, 5, 6, 7, or other layers.

[0077] For example, the diaphragm 20 is a three-layer structure, including two thermoplastic polyester elastomer layers and a film layer. The film layer is located between the two thermoplastic polyester elastomer layers and bonds the two thermoplastic polyester elastomer layers together.

[0078] Optionally, the elastomer layer includes one or more of thermoplastic polyurethane elastomer, thermoplastic polyamide elastomer, polystyrene elastomer, and polyolefin thermoplastic elastomer. The engineering plastic layer includes one or more of PEEK, PAR, PMI, PET, PEN, PA, PEI, and LCP. The film layer includes a silicone film and / or an acrylic film. The composite layer may be one or more layers.

[0079] According to another embodiment of the present invention, a sound generating device is provided. Figure 2-Figure 3 As shown, the sound-generating device 100 includes the diaphragm 20 of the above embodiment.

[0080] like Figure 2-Figure 3 As shown, the sound-generating device 100 may include a housing 10, a magnetic circuit system, and a vibration system. The magnetic circuit system includes a permanent magnet 40, which is used to form a magnetic gap. The vibration system includes a diaphragm 20 and a voice coil 30. The diaphragm 20 and the permanent magnet 40 are both connected to the housing 10. The permanent magnet 40 is disposed on one side of the diaphragm 20 along the thickness direction. One end of the voice coil 30 is connected to the diaphragm 20, and the other end is located in the magnetic gap.

[0081] In this example, the diaphragm 20 may be a surround diaphragm. The surround diaphragm comprises a central portion, a surround portion, and a fixed portion, connected in sequence from the inside out. The fixed portion is used to connect to the housing 10. A dome is provided on the central portion, and the voice coil 30 is connected to the central portion or the dome.

[0082] In other examples, the diaphragm 20 may also be a planar diaphragm or other structures. Those skilled in the art may determine this according to actual conditions, and no specific limitation is made here.

[0083] According to yet another embodiment of the present invention, an electronic device is provided.

[0084] The electronic device is, for example, a mobile phone, a computer, a television, a speaker, an intercom, a VR device, an AR device, smart glasses, etc. The electronic device includes the sound-generating device 100 described in the above embodiment. Of course, the electronic device of the present invention also includes at least all the beneficial effects of the above embodiment, which will not be described in detail here.

[0085] The diaphragm 20 and the sound generating device 100 of the present invention are described in detail below with reference to specific embodiments. It should be noted that the following description is merely exemplary and does not specifically limit the present invention.

[0086] Example: The diaphragm 20 has a three-layer structure, including two thermoplastic elastomer layers and a film layer. The film layer is located between the two thermoplastic polyester elastomer layers, bonding the two thermoplastic polyester elastomer layers together. The thickness of the thermoplastic elastomer layer is 12.5μm. The thickness of the film layer is 15μm. The diaphragm 20 is a ring-shaped diaphragm, and the overall shape is rectangular. The diaphragm 20 is formed by air pressure. The thermoplastic polyester elastomer layer is made of a blended material. The blended material includes a first thermoplastic polyester elastomer and a second thermoplastic polyester elastomer. The glass transition temperature of the first thermoplastic polyester elastomer is -39°C, and the ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 90%. The first thermoplastic polyester elastomer is copolymerized by a polytetrahydrofuran soft segment with a relative molecular weight of 2300 and a polybutylene terephthalate hard segment with a relative molecular weight of 2000 in a mass ratio of 1:1.

[0087] The second thermoplastic polyester elastomer has a glass transition temperature of -23°C, and the mass ratio of the second thermoplastic polyester elastomer to the total mass of the first and second thermoplastic polyester elastomers is 10%. The second thermoplastic polyester elastomer is copolymerized from a polybutylene adipate soft segment with a relative molecular weight of 3000 and a polybutylene terephthalate hard segment with a relative molecular weight of 2000 in a mass ratio of 6:4.

[0088] Comparative Example: The diaphragm 20 is a multi-layer structure, including two thermoplastic elastomer layers and a film layer. The film layer is located between the two thermoplastic polyester elastomer layers, bonding the two thermoplastic polyester elastomer layers together. The thickness of the thermoplastic elastomer layer is 13 μm. The thickness of the film layer is 15 μm. The diaphragm 20 is a ring-shaped diaphragm, and the overall shape is rectangular. The diaphragm 20 is formed by air pressure. The diaphragm 20 is made of thermoplastic polyester elastomer. The thermoplastic polyester elastomer is copolymerized by a polytetrahydrofuran soft segment with a relative molecular weight of 2300 and a polybutylene terephthalate hard segment with a relative molecular weight of 2000 in a mass ratio of 1:1. The glass transition temperature of the thermoplastic polyester elastomer is -39°C. The external dimensions of the comparative example diaphragm 20 are similar to those of the embodiment diaphragm 20. The F0 of the comparative example and the embodiment diaphragm 20 are basically the same. The comparative example diaphragm 20 and the embodiment diaphragm 20 are respectively assembled into a sound-generating device, which is a micro sound-generating device.

[0089] Test items: (1) The loss factor at 0°C, the 5-minute creep recovery rate and the room temperature storage modulus of the thermoplastic polyester elastomer layer of the comparative example and the example were tested.

[0090] Dissipation factor, also known as damping factor, is the ratio of loss modulus to storage modulus. It is measured using a dynamic thermomechanical analyzer according to ASTM D5026-23. The test environment is 0°C, the frequency is 1 Hz, and the strain is 0.2%.

[0091] Room temperature storage modulus was measured using a dynamic mechanical analyzer (DTM) according to ASTM D5026-23. The DTM was operated in tensile mode with a heating rate of 3°C / min and a frequency of 1 Hz.

[0092] The 5-minute creep recovery rate test method can be performed according to GB / T 11546.1-2008. The stress is 0.1 MPa, the holding time is 5 minutes, the creep time is 10 minutes, and the recovery time is 5 minutes.

[0093] (2) THD curves of the sound-generating devices of the embodiment and the comparative example.

[0094] Results and Analysis: After testing, the thermoplastic polyester elastomer layer of Example (1) has a loss factor of 0.078 at 0°C, a 5-minute creep recovery rate of 96.8%, and a room temperature storage modulus of 162 MPa.

[0095] The thermoplastic polyester elastomer layer of the comparative example has a loss factor of 0.066 at 0° C., a 5-minute creep recovery rate of 97.4%, and a room temperature storage modulus of 146 MPa.

[0096] As can be seen, the 5-minute creep recovery rate and room-temperature storage modulus of the thermoplastic polyester elastomer layer of the present invention embodiment are similar to those of the thermoplastic polyester elastomer layer of the comparative example, respectively. Their mechanical properties are similar. However, because the thermoplastic polyester elastomer film layer of the present invention embodiment includes a second thermoplastic polyester elastomer, it has a higher dissipation factor at 0°C and better damping performance.

[0097] (2) Figure 4 : The THD curves of the sound-generating device of the embodiment of the present invention and the sound-generating device of the comparative example. Figure 4 It can be seen that within the frequency range of 100Hz-1100Hz, the THD curve of the sound-generating device of the embodiment of the present invention is below the THD curve of the sound-generating device of Comparative Example 1. At the same frequency, the THD of the sound-generating device of the embodiment of the present invention is approximately 5%-15% lower than that of the sound-generating device of the comparative example. After the frequency is higher than 1100Hz, the THD curve of the sound-generating device of the embodiment of the present invention basically coincides with the THD curve of the sound-generating device of Comparative Example 1. This is because the low-temperature performance of the thermoplastic polyester elastomer layer is determined by its soft segment. However, lowering the glass transition temperature of the thermoplastic polyester elastomer layer will lead to a decrease in its loss factor at 0°C, which will aggravate the distortion of the diaphragm 20. Since the diaphragm 20 of the comparative example uses a single type of thermoplastic polyester elastomer layer, it is difficult to simultaneously meet the use requirements of low glass transition temperature and high loss factor. The diaphragm 20 of the embodiment is prepared by blending thermoplastic polyester elastomers with different glass transition temperatures. The soft segment of the first thermoplastic polyester elastomer with a low glass transition temperature is flexible and can provide low-temperature performance, and the hard segment has high crystallinity, which provides good heat resistance and creep recovery rate. It is not easy to break the membrane in high and low temperature environments, large amplitudes, and high frequencies. The good creep recovery rate can prevent the diaphragm 20 from slowly deforming under long-term stress. Near the resonant frequency F0, the chain segment of the second thermoplastic polyester elastomer with a high glass transition temperature transforms from a glassy state to a highly elastic state, thereby performing locally restricted motion, dissipating energy in the form of frictional heat, and improving the loss factor of the thermoplastic elastomer layer. Since the loss factor of the thermoplastic elastomer layer in the embodiment of the present invention is relatively high, the damping performance of the diaphragm is good.

[0098] In summary, since the thermoplastic polyester elastomer film layer of the diaphragm 20 of the embodiment of the present invention includes thermoplastic polyester elastomers with different glass transition temperatures, the damping of the diaphragm 20 can be effectively improved, so that the diaphragm 20 has better damping effect and excellent low-temperature performance.

[0099] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0100] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A diaphragm for a sound-generating device, characterized in that: The diaphragm includes at least one thermoplastic polyester elastomer layer; the thermoplastic polyester elastomer layer is prepared from a blended material, and the blended material includes a first thermoplastic polyester elastomer and a second thermoplastic polyester elastomer; the glass transition temperature of the first thermoplastic polyester elastomer is -65°C to -30°C, and the ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 30%-95%; the glass transition temperature of the second thermoplastic polyester elastomer is -25°C to 0°C, and the ratio of the mass of the second thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 5%-70%; the 5-minute creep recovery rate of the thermoplastic polyester elastomer layer is 70%-99%.

2. The diaphragm according to claim 1, wherein The ratio of the mass of the first thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 70%-90%, and the ratio of the mass of the second thermoplastic polyester elastomer to the total mass of the first thermoplastic polyester elastomer and the second thermoplastic polyester elastomer is 10%-30%.

3. The diaphragm according to claim 1, wherein The soft segment of the first thermoplastic polyester elastomer includes at least one of polytetrahydrofuran, polypropylene oxide, and polyethylene oxide. The mass percentage of the soft segment of the first thermoplastic polyester elastomer is 40%-80%, and the relative molecular weight of the soft segment of the first thermoplastic polyester elastomer is 1000-5000.

4. The diaphragm according to claim 1, wherein The soft segment of the second thermoplastic polyester elastomer includes at least one of an aliphatic polyester, an aromatic-aliphatic copolyester, an aliphatic polycarbonate, an aromatic polyether, and a copolyether. The mass percentage of the soft segment of the second thermoplastic polyester elastomer is 30%-60%, and the relative molecular weight of the soft segment of the second thermoplastic polyester elastomer is 800-3000.

5. The diaphragm according to claim 1, wherein: The blend material further includes an antioxidant, which includes at least one of a hindered phenol antioxidant, a phosphite antioxidant, and a thioether antioxidant, and the amount of the antioxidant added to the blend material is 0.1 phr-7 phr; And / or, the blended material further comprises an anti-hydrolysis agent, the anti-hydrolysis agent comprises at least one of monomeric carbodiimide, polycarbodiimide, and polycarbodiimide, and the amount of the anti-hydrolysis agent added to the blended material is 0.5 phr-5 phr; And / or, the blended material further comprises a light stabilizer, the light stabilizer comprising at least one of a benzotriazole light stabilizer, a triazine light stabilizer, a hindered amine light stabilizer, and a nickel quencher, and the light stabilizer is added to the blended material in an amount of 0.1 phr to 2 phr; And / or, the blended material further comprises a colorant, the colorant comprising at least one of phthalocyanine blue, phthalocyanine green, azo red, titanium dioxide, red iron oxide, carbon black, anthraquinones, and aluminum powder, and the amount of the colorant added to the blended material is 0.1 phr-5 phr; And / or, the blended material further includes a processing aid, which includes at least one of erucamide, oleamide, silica, diatomaceous earth, polydimethylsiloxane, ethylene wax, talc, and stearic acid additives, and the amount of the processing aid added to the blended material is 0.1phr-10phr.

6. The diaphragm according to claim 1, wherein: The thickness of the thermoplastic polyester elastomer layer is 5 μm-100 μm; and / or, the Young's modulus of the thermoplastic polyester elastomer layer at room temperature is 20 MPa-600 MPa; And / or, the density of the thermoplastic polyester elastomer layer is 1.10 g / cm 3 -1.30g / cm 3 .

7. The diaphragm according to claim 1, wherein: The melting temperature of the thermoplastic polyester elastomer layer is ≥185°C.

8. The diaphragm according to claim 1, wherein: The ratio of the melt index of the first thermoplastic polyester elastomer to the melt index of the second thermoplastic polyester elastomer is 0.5-2.

9. The diaphragm according to claim 1, wherein: After heat treatment at 160° C. for 96 hours, the thermoplastic polyester elastomer layer has a tensile strength decrease rate of ≤50%, and a Young's modulus decrease rate of ≤20%.

10. The diaphragm according to any one of claims 1 to 9, characterized in that: The diaphragm is formed into a single-layer structure, and the diaphragm is composed of a layer of the thermoplastic polyester elastomer; Alternatively, the diaphragm is formed into a multi-layer structure, the diaphragm includes at least one layer of the thermoplastic polyester elastomer layer and a composite layer, the composite layer is stacked with the thermoplastic polyester elastomer layer, and the composite layer is at least one of an elastomer layer, an engineering plastic layer and a film layer.

11. A sound-generating device, characterized in that: Comprising a diaphragm as described in any one of claims 1-10.

12. An electronic device, characterized in that: Comprising the sound-generating device as claimed in claim 11.

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